Grating



Jude 17, 1941. H. s. NAGIN 2,246,216

GRATING Filed Sept. 14, 1958 l 2 INVENTOR L v .Harr SCNQ 7J2 U L1: 5 11g Patented June 17, 1941 GRATING Harry S. Nagin, Pittsburgh, Pa.,assignor to Reliance Steel Products Company, RankimPa a corporation ofPennsylvania Application September 14, 1938, Serial No. 229,895

Claims.

This invention relates to ratings and is particularly directed togratings which have a skid proof or skid resistant surface and a methodof making the same.

Gratings comprising longitudinal bearing bars and cross bars extendinglaterally between and secured to the bearing bars are in common use forproviding a traffic supporting surface for both pedestrian and vehiculartraffic. The tops of said bars lie in substantially the same plane. Thesurface presented to the traflic by said structures is fairly skidresistant to some kind of traffic. The object of this invention is toenhance the skid resistant properties of the gratings.

I have found that the skid resistant properties of a grating to allsorts of trafiic may be greatly increased by serrating or indenting thetops of the bearing bars and the cross bars which comprise the trafiicsupporting surface. This is preferably done by a knurling or rollingoperation performed on the assembled grating after the grating has beenfabricated and While it is cold.

In the accompanying drawing, which illustrates the present preferredembodiment of my invention:

Figure 1 is a diagrammatic top plan View of a portion of a typicalgrating without serrations;

Figure 2 is a plan of ,a portion of a grating showing one form ofserrations;

Figure 3 is a plan View of a portion of a grating showing another formof serration;

Figure 4. is a section along the line IV-IV of Figure 2; s

Figure 5 is a plan of a portion of a grating showing still another formof serration; and

Figure 6 is a diagrammatic view in elevation of a suitable serratingapparatus.

In the drawing, there is illustrated a grating unit which consists of adesired number of longitudinal bearing bars or bearing members 2 ofpredetermined dimensions which are assembled in spaced apart parallelrelationship. At suitable intervals the bearing members v2 are securedto one another adjacent their tops by cross bars 3 which extendtransversely to the bearing members and are secured thereto in anyconvenient manner, preferably by pressure electric resistance welding.The tops of .the bearing members 2 and the tops of the cross bars 3,when joined, are in substantially the same plane and together form astructure presenting a reticulated traffic bearing surface. The bearingsurfaces of all the bars have serrations or indentations 4 thereonpreferably formed after the grating unit has been assembled and welded.All

t xposed ops of th be ri m mb s a the ad a nt ross ba ar s rate he in entions may all run in a common direction and uniformly over the bearingmember and the cross bar as shown n igu 2. o t r a s may run n on directon a o bea member and t e ad acent ha 91" the c o s r and in a ferentdirection on the adjoining bearing members and the halves of the crossbars adjacent to them, as shown Figure 3. Again, the bearing members andthe cross bars may each be knurled to form pyramids or like projectionsor indentations. The prime object to provide some sort of serrations onthe top exposed surfaces of the bearing members and the cross bars toincrease the skid resistant Properties of the grating.

It will be observed that the top surfaces of the bars are slightlywidened at the top '5 by the serrating operation. This is shown, forexample, in Figure 4, where it will be observed that the top surface ofthe cross bar is wider than the adjacent portion of the cross bar. Thisgives a slightly wider metal surface to be presented to the trafiic andretards wear of the surface.

In making my grating unit I first assemble the bearing bars 2 and thecross bars 3 of the desired dimensions and in the desired relationshipand thenunite them, preferably by pressure electric resistance welding.This part of the process is old. I then pass the welded unit between apair .of rollers, the surface .of the rollers in contact with the .topsurfaces of the unit being suitably shaped so as to impressor roll thedesired serrations onto the bearing bars and the cross bars.

Apparatus suitable for serrating the top surfaces of the grating isshown in Figure 6. The apparatus consists of an upper roll 6 which maybe solid .or may be made .up of discs fixedly mounted on a shaft 1, anda lower roll 8. The upper roll 6 has surface projections thereon forserrating the grating. The lower roll 8 has an ordinary cylindricalsurface.

Gratings so formed are highly skid resistant; are inexpensive tomanufacture, since the increased cost involved in serrating the surfaceis but very little. By rolling in or pressure forming the indentations,the original skin on .the bar edges is not injured and this originalskin is more resistant to wear and to corrosion than is a surface whichhas been broken or cut. The'rolling in of the indentation also producesthe flare at the upper edge of the grating bars, and avoids theformation of sharp cutting edges such as might injure one who might fallon the grating. The serrated surface is preferably such that the Whilemy grating is particularly useful as an open type grating, it can beused to advantage as a reinforcing unit for a cementitious body. Thearmoured surface of the completed cementitious body is rendered somewhatmore skid resistant by the use of grating units having skid resistantproperties of the character imparted to it according to my invention. Itis to be understood that the bearing bars and cross bars could beserrated before being assembled in the "unit, but this type ofconstruction is somewhat more expensive and a less satisfactory jointresults.

WhileI have illustrated and described certain preferred embodiments of.my invention, it is not limited thereto, but may be otherwise embodiedand practiced within the scope of the following claims:

I claim: 1. Agrating or the like fabricated from continuous separatebars of metal having fiat surfaces, comprising wrought metal bearingmembers and cross bars rectangular in cross section disposed angularlywith respect to said bearing members and secured thereto by pressureelectric resistance welding, the top edges of said members and of saidbars constituting tread surfaces throughout their lengths and beingindented to provide serrations, the tops of the serrations lyinginsubstantially the same plane, said serrations being angularly disposedto the longitudinal axis of the bearing'members and to the longitudinalaxis of. the cross bars, the serrations of adjoining parts continuinguninterruptedly from a bearing member into an adjoining cross bar.

2. A grating or the like fabricated from continuous separate bars ofmetal having flat surfaces, comprising wrought metal longitudinalbearing members, wrought metal cross bars rectangular in cross sectiondisposed angularly with respect to said bearing members and securedthereto by pressure electric resistance welding,

the top edges of said members and of said bars constituting treadsurfaces throughout their lengths and being provided with rolledserrations, the tops of the serrations lying in substantially the sameplane, said serrations being angularly disposed to the longitudinal axisof the bearing constituting tread surfaces throughout their lengths andbeing slightly widened at the top and of substantially constantthickness throughout the remainder of their sections, and beingserrated, the tops of the serrations lying in substantially the sameplane, said serrations being angularly disposed to the longitudinal axisof the bearing members and the longitudinal axis of the cross bars, theserrations of adjoining parts continuing uninterruptedly from onebearing member into an adjoining cross bar.

4. An assembled grating comprised of two sets of angularly disposedcontacting bars fixedly joined at their points of contact and havingtheir top surfaces in a plane, all of the bars being serrated over theirentire top surface, there being laterally extending portions along thetop edges of. the bars, the grooves between the serrations at thejunctions of the bars being in register and continuing uninterruptedlyacross the area of the junction and intothe adjoining bars and beingangularly disposed to the longitudinal axes of both sets of bars.

5. A grating or the like fabricated from continuous separate bars ofmetal having flat surfaces, comprising wrought metal longitudinalbearing members, Wrought metal cross bars rectangular in cross sectiondisposed angularly with respect to said bearing members and securedthereto by pressure electric resistance welding, the top edges of saidmembers and of said bars constituting tread surfaces throughout theirlengths and being indented to provide serrations, the tops of theserrations lying in substantially the same plane, said serrations being"angularly disposed to the longitudinal axis of the bearing members andto the longitudinal axis of the cross bars, the serrations on alternatebearing members and the adjoining portions of. the cross bars runninginone direction and continuing uninterruptedly from one member into theadjoining portions of the cross bars, while the serrations on thebearing members intermediate the alternate members and on the portionsof the cross bars adjoining the intermediate members run in anotherdirection.

HARRY S. NAGIN.

